@Ant,
Looking forward to next screenies. It's been a marathon for you but sure it will be worth it!
I imagine the end RPG HeroKit product will also include a 'fair few' additional HeroActions...
Looking forward also to seeing your thinking on formulae and, maybe, custom databases.

@Ant, @AK-i,
If custom databases could be created in HeroKit that would also single-handedly both massively enhance the flexibility of the product and do away with concerns re lack of Arrays and Lists.
Rarity and Chance to loot pretty essential for loot tables and these and value need to be alterable from items, sockets and affixes.
Inventory weight for each item and 2d xy size for each item are key to inventory management.

@Ant,
Starting Stats, Abilities, meters etc.. allow for starting minimum or starting bonus per Race, Subrace, Class etc.
Think you also need a database covering (similar to Class or Race with Types) custom things like say Star Sign, Nationality etc up to programmer.
That might also cover Religions. Otherwise religions database. Character religion. Thinking Gods n Pantheons etc with most classic RPGs...
Reputations database?
Have you done Alignments database?
Starting Alignments? That's v useful if can have more than one. I.e. lawful to chaos, good to evil, law abiding to crime, nature to science etc.
Brushing up here a bit...
Sorry didn't think of it before recently but ... Loot weight (chance) and loot tables...?
Also, with Items, Inc Weapons etc, did you cover off their weight and, optionally, how many squares X and Y they cover when contained? Also, container items? Also, if equippable, to what equipment slots?
Equipment Slot database?

@ChiaPet, @AK-i,
I have a working theory that a combination of the free Manuel Bastioni plugin for Blender, perhaps Cloth Weaver paid for plugin for Blender and the VM Skinn Asset may leave us to the promised land.... But don't quote me.

@Ant,
How are you going to tackle the whole thorny issue of temporary, over time and straight modifiers to meters, attributes/stats and abilities?
Worth checking out the free CharacterStats asset on the Asset Store (and associated YouTube vids). His coding ideas are v clever and basically allow for any number of modifiers on any number of stats...

@Ant,
Let's say your RPG has DnD-esque attributes which typically max out at 18...
You cannot them say select or choose or become a Warrior unless your STAR (Strength) attribute is at least 14. Similarly, being a Mage requires a minimum of 14 for Intelligence etc etc. Class requirements on attributes may require more than one attribute minimum value.
Hope that makes sense?

@Ant,
What ChiaPet said.
Also, assuming lots of weapons and weapon types, may be better to list ones excluded rather than allowed? Similarly Armour Types but Ability Types best this way round...
I'd also suggest min Attribute(s) for Class as option as well,

@Ant,
Congrats on breaking the back of these databases!
Got a couple of things I'm not sure on re above.
Why mention of wooden and iron ? Are they weapon types or just specific weapons?
Also with conditions and elements, why strong and weak and why not just use percentages? Percentages more exact?
With Classes (and SubClasses?) and Races and SubRaces do we optionally need Alignments restrictions?
Would certain Classes be limited to certain Races (but this perhaps managed from Races database)?
Hoping you're going to do experience and progression with ranks/levels with Classes? How would that effect Class abilities etc?
Minimum attributes?
[edit] just read your bit about 'a lot more to do'.... !

@Ant,
Looks spot on above.
Subraces are a staple of many RPGs. So, an example...
Race = Elf
Subraces = High Elf
The Race might modify some stats and meters and resistances. The SobRace might do the same and tweak things.
Also Subraces tend to add cultural things like starting items and available options for character looks, alignments, relationships, reputations, religion etc.